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REVIEW 4 major objections 6 minor 1 cited by

An Introduction to Variational Quantum Eigensolver Applied to Chemistry

T0 review · 4 major / 6 minor · reviewed 2026-08-15 · deepseek-v4-flash

Pith's one-line read A full cost model for VQE chemistry yields scaling of N^9 over error squared.

desk verdict A competent Portuguese-language tutorial on VQE for chemistry, not a research advance; the complexity scalings are standard, and the main caveat is that the quoted O(N^9/epsilon^2) and O(kN^7/epsilon^2) are per-evaluation costs, not the full VQE cost including optimizer iterations. read the letter →

arxiv 2505.04768 v2 pith:4HJVYGXL submitted 2025-05-07 quant-ph physics.chem-ph

classification quant-phphysics.chem-ph
keywords VQEquantumchemistrycomputationalcomplexityJordan-WignermappingunitarycoupledclusterTrotterizationmeasurementscalingbarrenplateaus
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper is a self-contained introduction to using the Variational Quantum Eigensolver (VQE) to find molecular ground-state energies, and it ends by deriving the computational cost of evaluating the VQE cost function rather than benchmarking a new method. It claims that for a molecule described by N electrons (with 2N spin-orbitals) under the Jordan-Wigner mapping, a UCC or UCCG ansatz needs circuit depth O($N^{5}$), about O($N^{4}$/$epsilon^{2}$) measurements, and hence total time O($N^{9}$/$epsilon^{2}$) per cost-function evaluation. The k-UpCCG ansatz lowers this to O($kN^{3}$) depth and O($kN^{7}$/$epsilon^{2}$) total, where k is the number of repeated layers. A careful reader should care because these scalings say where VQE becomes impractical: not only on noisy devices but even with idealized hardware, unless the Pauli-term count or measurement number can be reduced.

What carries the argument

The machinery is the decomposition of the variational unitary U(theta) = exp(sum_j -i theta_j P_j / 2) into Trotter steps, combined with the replacement of each single Pauli exponential by a circuit whose depth is linear in the Pauli weight. The named objects are the Jordan-Wigner mapping, which assigns one qubit to each spin-orbital and enforces fermionic antisymmetry with chains of Z operators, and the ansatze UCC, UCCG, and k-UpCCG. The sequential-term count is treated as the number of Pauli terms because Jordan-Wigner strings have average weight N/2, so parallelization across disjoint qubits is rare; the Trotter step count l is absorbed into the optimizable angles theta_j, which removes l from the quoted depth.

What would settle it

Run a UCCSD VQE for a small molecule with increasing basis size (for example, water from STO-3G toward cc-pVTZ), fix chemical accuracy at 1.6 mHa, and record both the Trotter step count and the total circuit depth as functions of N; if depth grows faster than $N^{5}$ because the Trotter step count increases with N, the paper's central scaling estimate fails.

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Extended reading notes

Core claim

On the paper's own terms, the central claim is that the practical cost of VQE for chemistry can be computed from three pieces: the number of cluster amplitudes, the average Pauli weight of Jordan-Wigner strings, and the number of measurements needed to reach precision epsilon. Counting cluster amplitudes gives O($N^{4}$) Pauli terms for UCC and UCCG and O($kN^{2}$) for k-UpCCG; because Jordan-Wigner Pauli strings have average weight N/2 and different strings can rarely be parallelized, the circuit depth becomes O($N^{5}$) and O($kN^{3}$). Since the molecular Hamiltonian decomposes into O($N^{4}$) Pauli strings, the measurement count is O($N^{4}$/$epsilon^{2}$), and the per-step cost-function evaluation becomes O($N^{9}$/$epsilon^{2}$) for UCC/UCCG and O($kN^{7}$/$epsilon^{2}$) for k-UpCCG, with the optimizer's own step count left outside the estimate.

Load-bearing premise

The quoted scalings assume that the number of Trotter steps can be absorbed into the variational parameters, so it does not grow with system size or required accuracy; if real chemical accuracy forces that number to grow, the depth and total-cost estimates are too low.

Editorial extensions

If this is right

  • At fixed chemical accuracy, adding basis functions makes VQE dramatically more expensive: UCC and UCCG depth grows as N^5 and measurements as N^4, so the per-step cost grows as N^9.
  • The k-UpCCG ansatz is the only one of the three whose quoted depth, O(kN^3), might fit inside near-term coherence times for modest N, but its total cost O(kN^7/epsilon^2) still grows quickly enough to question a practical quantum advantage.
  • Measurement count, not just gate depth, is a bottleneck: O(N^4/epsilon^2) shots are needed before optimization even begins, so reducing the number of Pauli terms or grouping them into commuting families would improve the total scaling directly.
  • Because the optimizer's number of cost-function evaluations is left undetermined, the quoted costs are lower bounds on actual wall-clock time; barren-plateau landscapes can make that number large and also force higher measurement precision.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the Trotter step count l must grow with system size or with 1/epsilon to maintain chemical accuracy, the depth scalings O(N^5) and O(kN^3) are optimistic; a direct count of l as a function of N for small molecules would test this.
  • The same counting logic, applied to low-Paulie-weight encodings, suggests that the depth factor could be reduced while the O(N^4/epsilon^2) measurement term remains, changing the quoted total cost.
  • The O(N^4/epsilon^2) measurement bound is a conservative per-string estimate; grouping Pauli terms into commuting families could replace the number of terms by the number of groups and lower the total cost in practice.
  • The paper's analysis covers one cost-function evaluation; the full VQE runtime is X + (I+P)QK, so any end-to-end complexity claim must also account for the classical optimizer cost, which the paper deliberately leaves empirical.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 6 minor

Summary. The paper is a Portuguese-language pedagogical review of the Variational Quantum Eigensolver (VQE) applied to molecular electronic structure. It develops the required background in quantum chemistry, second quantization, basis sets, and the UCC/UCCG/k-UpCCG ansätze, and then presents a theoretical complexity analysis in Section 5. For a molecule described by N basis functions per spin with Jordan-Wigner encoding, the paper derives a variational circuit depth O(N^5) for UCC/UCCG and O(kN^3) for k-UpCCG, a measurement count O(N^4/epsilon^2), and per-evaluation costs O(N^9/epsilon^2) and O(kN^7/epsilon^2), stated in Eqs. (52) and (53). It closes with a discussion of NISQ limitations, especially barren plateaus.

Significance. If correct, these estimates would form a useful consolidation of known scaling results for practitioners and students: the paper explicitly separates preprocessing, initial state preparation, circuit depth, measurement, and optimizer iterations in Eq. (44), and it gives helpful worked examples such as Hartree-Fock state preparation and the decomposition of a single Pauli exponential. The bibliography is broad and the review is readable. However, the central quantitative claims are not new, and several load-bearing steps are either heuristic or inconsistent with the paper's own complexity framework. The paper therefore cannot currently serve as a reliable reference for the scaling of VQE, but the issues are localizable and correctable in revision.

major comments (4)
  1. [Section 5, Eq. (44); Section 5.2, Eqs. (52)-(53); Section 6] The paper defines the total VQE complexity in Eq. (44) as X + (I+P)·Q·K and explicitly states that K will not be calculated because it depends on unpredictable factors. The text around Eqs. (52)-(53) then calls O(N^9/epsilon^2) and O(kN^7/epsilon^2) the 'cálculo da função custo total', and Section 6 refers to O(kN^7/epsilon^2) as the 'complexidade total' of the method. These statements identify the per-evaluation cost (I+P)·Q with the total algorithm cost. Since K is not a constant and can scale with N and with the required accuracy (a point the paper itself makes in the barren-plateau discussion), the headline total-cost scalings are not established. The claims should be explicitly reworded as per-cost-function-evaluation costs, or the K-dependence must be included.
  2. [Section 5.1, Trotterization paragraph] The text states that the factor 1/l in the Trotterized exponential can be absorbed into the optimizable parameters theta_j so that the circuit becomes a sequence of Pauli exponentials. Absorbing 1/l changes the angle values, but the circuit still contains l repetitions of the entire Trotter step, so the circuit depth is multiplied by l. The Trotter error is O(1/l) and depends on the commutators of the Pauli terms; for fixed chemical accuracy, l will in general grow with N and with 1/epsilon. The reported depths O(N^5) and O(kN^3) are therefore per Trotter step, not total circuit depths, unless an explicit argument is supplied that l = O(1) suffices. This gap is load-bearing for the final scaling claims.
  3. [Section 5.2, Eqs. (49)-(51)] The measurement scaling O(N^4/epsilon^2) is derived from S_i ≈ Var(P_i)/epsilon^2 per term and then summing over M terms. This is a per-term precision budget, not a total-error budget: if each of the M = O(N^4) terms is measured to precision epsilon, the variance of the summed estimator is approximately M·epsilon^2, so the total error grows as sqrt(M). To achieve total error epsilon, the per-term precision must be epsilon/sqrt(M), yielding at least O(M^2/epsilon^2) = O(N^8/epsilon^2) shots under the independent-measurement strategy used here (or O((sum |c_i|)^2/epsilon^2) with coefficient-aware allocation). This changes the Q factor in Eqs. (52) and (53) and should be corrected or explicitly justified as a different estimation strategy.
  4. [Section 5.1, sequential-term count] The paper asserts that because the average Jordan-Wigner Pauli weight is N/2, the number of sequential exponentials is of the same order as the total number of terms. This is a heuristic statement, not a derivation: the minimum depth of a scheduled circuit depends on the conflict graph of the Pauli supports, and an average-weight argument does not bound the chromatic number of that graph. Since the circuit depth P depends directly on this sequential count, the authors should either provide a counting or scheduling argument or explicitly flag this step as an assumption.
minor comments (6)
  1. [Section 5.1, Eq. (47)] The formula presented after 'a partir do teorema de Baker-Hausdorff' is the Zassenhaus expansion, not the Baker-Campbell-Hausdorff formula; the terminology should be corrected.
  2. [Section 5, preprocessing discussion and Eq. (52)] The text says practical Hartree-Fock scales as O(N^3) for many problems, but the summary paragraph before Eq. (52) states that preprocessing grows as O(N^4); these two statements should be reconciled.
  3. [Section 5.1] The assumption N_f = 2N_e = 2N is introduced for the big-O analysis but its effect on the constants and on the range of chemical systems covered is not discussed; it should be stated more prominently.
  4. [Page 33, Section 5.1] There are typographical slips: 'Bravye-Kitaev' and 'Jorda-Wigner' should read 'Bravyi-Kitaev' and 'Jordan-Wigner'.
  5. [Section 2.2, Eq. (5)] The electron-electron repulsion sums in Eqs. (3) and (5) run over all i,j without excluding i=j; the standard expression should use i<j (or include the explicit ordering), otherwise the divergent self-interaction terms are formally present.
  6. [Section 5.2] The commonly cited 'chemical accuracy' threshold of 1.6 mHa is attributed to the Pople Nobel lecture; a more specific reference for this convention would be helpful.

Circularity Check

0 steps flagged · score 0.0 of 10

No load-bearing circularity: VQE complexity estimates are a self-contained arithmetic synthesis of external results, with overstatement caveats that are correctness issues, not circular reductions.

full rationale

The paper is a tutorial review of VQE applied to chemistry, not a work that fits parameters and then predicts them back. Its central complexity estimates are arithmetic compilations of independent pieces: I=1 for Hartree-Fock state preparation is constructed explicitly; P is obtained by explicit combinatorial term counts (O(N^4) for UCC/UCCG, O(kN^2) for k-UpCCG) times the average Jordan-Wigner Pauli weight O(N); Q is obtained from Var(P_i)/epsilon^2 summed over O(N^4) Hamiltonian terms. These pieces are then multiplied in Eqs. (52) and (53). No step equates a fitted parameter with the claimed prediction. The references used for the Pauli-exponential decomposition, Trotterization, and k-UpCCG term structure are external works with stated assumptions, and the few author self-citations concern basis functions, tunneling, and trapped-ion hardware and are not load-bearing. Two caveats are correctness and scope issues rather than circularity: (i) Eq. (44) defines total cost with K, but Section 5 explicitly does not compute K, so the later 'complexidade total' statements in Eqs. (52)-(53) and the conclusion are per-evaluation costs unless K is O(1); (ii) the depth estimate absorbs the Trotter step count l into the optimizable theta_j, which is an assumption that l is constant or otherwise negligible, not a derivation from the Trotter formula. Both issues are flagged by the paper's own equations and caveats, and neither involves a circular reduction of the conclusion to the premises.

Assumptions & free parameters 2 free parameters · 5 assumptions · 0 invented entities

The paper does not introduce new physical entities. Its central claims rest on standard quantum chemistry and quantum computing background, plus two heuristic complexity assertions in Section 5.1: the absorption of Trotter step count into variational parameters and the average Pauli weight N/2. These two assertions are the main fragile assumptions in the presented scaling.

free parameters (2)
  • Number of Trotter steps l = Not specified; assumed absorbable into variational parameters theta_j
    Section 5.1 states that the 1/l factor can be absorbed into the optimizable parameters theta_j. This removes l from the scaling analysis without quantifying the Trotter error or proving that l can be held constant while maintaining chemical accuracy. This is a hand-waved parameter that affects the central complexity claim.
  • Trotter order = First order (implicitly)
    The paper uses the first-order Trotter formula and does not discuss higher-order formulas. The error term O(1/l) is quoted, but no explicit bound on the number of steps is derived, so the accuracy as a function of system size and target precision is not quantified.
assumptions (5)
  • domain assumption The Born-Oppenheimer approximation is valid for the molecular systems considered.
    Section 2.2 introduces the Born-Oppenheimer approximation as the basis for the electronic Hamiltonian. This is standard in quantum chemistry and limits the validity to cases where nuclear and electronic motion decouple.
  • standard math The variational principle holds for the chosen ansatz.
    Section 2.1 states the variational principle that the expectation value of the Hamiltonian is an upper bound to the ground-state energy. This is a standard theorem in quantum mechanics.
  • standard math Fermionic anti-commutation relations are correctly mapped by the Jordan-Wigner transformation.
    Section 4.3 assumes the Jordan-Wigner mapping preserves the anti-commutation relations of creation and annihilation operators. This is a standard result in quantum information.
  • ad hoc to paper The average Pauli weight of Jordan-Wigner strings is N/2.
    Section 5.1 uses the claim that the average Pauli weight is N/2 for the Jordan-Wigner encoding. This is a stated assertion without a detailed derivation, and it is central to the depth estimate O(N) per Trotter step.
  • ad hoc to paper The number of sequential Trotter terms is of the same order as the total number of terms.
    Section 5.1 argues that because the average Pauli weight is high, there is little room for parallelization, so the number of sequential terms is O(N^4) for UCC and O(k N^2) for k-UpCCG. This is an heuristic counting argument, not a rigorous scheduling analysis.

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Pith. "Pith review of An Introduction to Variational Quantum Eigensolver Applied to Chemistry." pith.science (2026). https://pith.science/paper/4HJVYGXL

@misc{pith2026250504768,
  author       = {Pith},
  title        = {Pith review of: An Introduction to Variational Quantum Eigensolver Applied to Chemistry},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/4HJVYGXL}},
  note         = {Machine review of arXiv:2505.04768}
}
abstract

Quantum mechanics has introduced a new theoretical framework for the study of molecules, enabling the prediction of properties and dynamics through the solution of the Schr\"odinger equation applied to these systems. However, solving this equation is computationally expensive, which has led to the development of various mathematical frameworks and computational methods designed to balance the available resources with the desired level of accuracy. In particular, quantum computers have emerged as a promising technology with the potential to address these problems more efficiently in the coming decades, whether through reductions in memory, time, and energy consumption, $\textit{i. e.}$, reductions in computational complexity or by enhancing precision. This research field is known as Quantum Simulation. Given the current technological limitations of quantum computers, Variational Quantum Algorithms (VQAs), especially the Variational Quantum Eigensolver (VQE), stand out as a feasible approach to demonstrating advantages over classical methods in the near term. This feasibility arises from their lower demand for quantum gates and the reduced depth of the circuits required for their implementation. In this work, we present the application of quantum mechanics to the study of molecules, provide an introduction to the fundamentals of quantum computing, and explore the integration of these fields by employing the VQE in molecular simulations. Finally, we discuss the spatial and temporal complexity associated with the algorithm, highlighting its implications and challenges.

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Reference graph

Works this paper leans on

97 extracted references · 71 canonical work pages · cited by 1 Pith paper

  1. [1]

    Quantum computing.Reports on Progress in Physics, 61:117–173, 2 1998

    Andrew Steane. Quantum computing.Reports on Progress in Physics, 61:117–173, 2 1998

  2. [2]

    precisão química

    Consideramos um caso que o número de elétrons são pares, comne en f os números de orbitais ocupados e virtuais, respecticamente. utilizadasN f funções de base de1elétron para re- presentar um sistema deNe elétrons, a realização de cada passo da iteração escala comO(N4 f )devido às integrais de termos de dois corpos, que possuem quatro funções de base cada...

  3. [3]

    Quantum computers and quantum computations.Physics-Uspekhi, 48:1–36, 1 2005

    Kamil’ A Valiev. Quantum computers and quantum computations.Physics-Uspekhi, 48:1–36, 1 2005

  4. [4]

    Zoller, Th

    P. Zoller, Th. Beth, D. Binosi, R. Blatt, H. Briegel, D. Bruss, T. Calarco, J. I. Ci- rac, D. Deutsch, J. Eisert, A. Ekert, C. Fa- bre, N. Gisin, P. Grangiere, M. Grassl, S. Haroche, A. Imamoglu, A. Karlson, J. Kempe, L. Kouwenhoven, S. Kröll, G. Leu- chs, M. Lewenstein, D. Loss, N. Lütkenhaus, S. Massar, J. E. Mooij, M. B. Plenio, E. Polzik, S. Popescu, ...

  5. [5]

    Richard P. Feynman. Simulating physics with computers.International Journal of Theoreti- cal Physics, 21:467–488, 1982

  6. [6]

    Preskill

    J. Preskill. Quantum computing and the en- tanglement frontier.arXiv, 2021

  7. [7]

    Quantum com- putations with cold trapped ions.Physical re- view letters, 74(20):4091–4094, 1995

    Juan I Cirac and Peter Zoller. Quantum com- putations with cold trapped ions.Physical re- view letters, 74(20):4091–4094, 1995

  8. [8]

    Universal quantum simulators

    Seth Lloyd. Universal quantum simulators. Science, 273:1073–1078, 8 1996

Show all 97 references
  1. [9]

    Quantum manifesto for quantum technologies, 2016

    Aymard de Touzalin, Charles Marcus, Freeke Heijman, Ignacio Cirac, Richard Murray, and Tommaso Calarco. Quantum manifesto for quantum technologies, 2016

  2. [10]

    Blatt and D

    R. Blatt and D. Wineland. Entangled states of trappedatomicions. InT.BethandG.Leuchs, editors,Quantum Information Processing, pa- ges143–160.Wiley-VCH,Weinheim, Germany, 2005

  3. [11]

    M. A. Nielsen and I. L. Chuang.Quan- tum Computation and Quantum Information. Cambridge University Press, Cambridge, En- gland, 2nd edition, 2010. Cited pages: 5, 6, 13–15, 20, 111–118, 175

  4. [12]

    Use vqe to calcu- late the ground energy of hydrogen molecules on ibm quantum.arXiv, 5 2023

    Maomin Qing and Wei Xie. Use vqe to calcu- late the ground energy of hydrogen molecules on ibm quantum.arXiv, 5 2023

  5. [13]

    Peter W. Shor. Polynomial-time algorithms for prime factorization and discrete logarithms on a quantum computer.SIAM Journal on Com- puting, 26:1484–1509, 10 1997

  6. [14]

    Lov K. Grover. A fast quantum mechanical algorithm for database search.arXiv, 5 1996

  7. [15]

    Love, Alán Aspuru-Guzik, and Jeremy L

    Alberto Peruzzo, Jarrod McClean, Peter Shad- bolt, Man-Hong Yung, Xiao-Qi Zhou, Pe- ter J. Love, Alán Aspuru-Guzik, and Jeremy L. O’Brien. A variational eigenvalue solver on a photonic quantum processor.Nature Commu- nications, 5:4213, 7 2014

  8. [16]

    Variational quan- tum simulation for quantum chemistry.Advan- ced Theory and Simulations, 2, 4 2019

    Yifan Li, Jiaqi Hu, Xiao-Ming Zhang, Zhigang Song, and Man-Hong Yung. Variational quan- tum simulation for quantum chemistry.Advan- ced Theory and Simulations, 2, 4 2019

  9. [17]

    The variational quantum eigensolver: areviewofmethodsandbestprac- tices.Physics Reports, 986:1–128, 2022

    Jules Tilly, Hongxiang Chen, Shuxiang Cao, Dario Picozzi, Kanav Setia, Ying Li, Edward Grant, Leonard Wossnig, Ivan Rungger, Ge- orge H Booth, et al. The variational quantum eigensolver: areviewofmethodsandbestprac- tices.Physics Reports, 986:1–128, 2022

  10. [18]

    Frey, Christof Holzer, Wim Klop- per, and Samuel Leutwyler

    Jann A. Frey, Christof Holzer, Wim Klop- per, and Samuel Leutwyler. Experimen- tal and theoretical determination of dissocia- tion energies of dispersion-dominated aroma- tic molecular complexes.Chemical Reviews, 116(9):5614–5641, April 2016

  11. [19]

    Junwei Lucas Bao and Donald G. Truhlar. Va- riational transition state theory: theoretical framework and recent developments.Chemi- cal Society Reviews, 46(24):7548–7596, 2017

  12. [20]

    Pearson, Upper Saddle River, NJ, USA, 7 edition, Fe- bruary 2013

    Ira N Levine.Quantum chemistry. Pearson, Upper Saddle River, NJ, USA, 7 edition, Fe- bruary 2013

  13. [21]

    Porto and Nelson H

    Caio M. Porto and Nelson H. Morgon. Analy- tical approach for the tunneling process in double well potentials using irc calculati- ons.Computational and Theoretical Chemis- try, 1187:112917, October 2020

  14. [22]

    Oppenheimer

    M Born and R. Oppenheimer. Zur quan- tentheorie der molekeln.Annalen der Physik, 389:457–484, 1927

  15. [23]

    AntonioFernandoRibeiroDeToledoPiza.Me- cânica Quântica Vol. 51. EdUSP, São Paulo, Brazil, 2003

  16. [24]

    Funções de base: o ajuste variacional.Re- vista Chemkeys, (2):1–11, 2001

    Nelson Henrique Morgon and Rogério Custó- dio. Funções de base: o ajuste variacional.Re- vista Chemkeys, (2):1–11, 2001

  17. [25]

    The wave mechanics of an atom with a non-coulomb central field

    Douglas R Hartree. The wave mechanics of an atom with a non-coulomb central field. part i. theory and methods.Mathematical Procee- dings of the Cambridge Philosophical Society, 24(1):89–110, 1928

  18. [26]

    Näherungsmethode zur lö- sung des quantenmechanischen mehrkörper- problems.Zeitschrift für Physik, 61:126–148, 1930

    Vladimir Fock. Näherungsmethode zur lö- sung des quantenmechanischen mehrkörper- problems.Zeitschrift für Physik, 61:126–148, 1930

  19. [27]

    Ostlund.Modern Quantum Chemistry: Introduction to Advan- ced Electronic Structure Theory

    Attila Szabo and Neil S. Ostlund.Modern Quantum Chemistry: Introduction to Advan- ced Electronic Structure Theory. Dover Publi- cations, Mineola, NY, USA, 1996. 36

  20. [28]

    John Wiley & Sons, Nashville, TN, USA, 2 edition, January 2007

    Frank Jensen.Introduction to Computational Chemistry. John Wiley & Sons, Nashville, TN, USA, 2 edition, January 2007

  21. [29]

    Funções de base: o ajuste variacional.Re- vista Chemkeys, (2):1–11, September 2018

    Nelson Henrique Morgon and Rogério Custó- dio. Funções de base: o ajuste variacional.Re- vista Chemkeys, (2):1–11, September 2018

  22. [30]

    W. J. Hehre, R. F. Stewart, and J. A. Po- ple. Self-consistent molecular-orbital methods. i. use of gaussian expansions of slater-type ato- mic orbitals.The Journal of Chemical Physics, 51(6):2657–2664, September 1969

  23. [31]

    Stephen Binkley, John A

    J. Stephen Binkley, John A. Pople, and War- ren J. Hehre. Self-consistent molecular orbi- tal methods. 21. small split-valence basis sets for first-row elements.Journal of the Ameri- can Chemical Society, 102(3):939–947, January 1980

  24. [32]

    Ditchfield, W

    R. Ditchfield, W. J. Hehre, and J. A. Pople. Self-consistent molecular-orbital methods. ix. an extended gaussian-type basis for molecular- orbital studies of organic molecules.The Jour- nal of Chemical Physics, 54(2):724–728, Janu- ary 1971

  25. [33]

    Gordon, J

    Mark S. Gordon, J. Stephen Binkley, John A. Pople, William J. Pietro, and Warren J. Hehre. Self-consistent molecular-orbital methods. 22. small split-valence basis sets for second-row elements.Journal of the American Chemical Society, 104(10):2797–2803, May 1982

  26. [34]

    Krishnan, J

    R. Krishnan, J. S. Binkley, R. Seeger, and J. A. Pople. Self-consistent molecular orbital methods. xx. a basis set for correlated wave functions.The Journal of Chemical Physics, 72(1):650–654, January 1980

  27. [35]

    W. J. Hehre, R. Ditchfield, and J. A. Pople. Self—consistent molecular orbital methods. xii. further extensions of gaussian—type basis sets for use in molecular orbital studies of orga- nic molecules.The Journal of Chemical Phy- sics, 56(5):2257–2261, March 1972

  28. [36]

    Basis sets in quantum chemistry

    Balazs Nagy and Frank Jensen. Basis sets in quantum chemistry. In Abby L. Parrill and Kenny B. Lipkowitz, editors,Reviews in Com- putational Chemistry, chapter 3, pages 93–149. Wiley, Nova Jersey, USA, 2017

  29. [37]

    Johnson, Alberto Otero-de-la Roza, Stephen G

    Erin R. Johnson, Alberto Otero-de-la Roza, Stephen G. Dale, and Gino A. DiLabio. Effi- cient basis sets for non-covalent interactions in xdm-corrected density-functional theory.The Journal of Chemical Physics, 139(21), Decem- ber 2013

  30. [38]

    Kirschner, Dirk Reith, and Wolfgang Heiden

    Karl N. Kirschner, Dirk Reith, and Wolfgang Heiden. The performance of dunning, jensen, and karlsruhe basis sets on computing relative energies and geometries.Soft Materials, 18(2- 3):200–214, 2020

  31. [39]

    Pitman, Alicia K

    Samuel J. Pitman, Alicia K. Evans, Robbie T. Ireland, Felix Lempriere, and Laura K. Mc- Kemmish. Benchmarking basis sets for den- sity functional theory thermochemistry cal- culations: Why unpolarized basis sets and the polarized 6-311g family should be avoi- ded.The Journal o...

  32. [40]

    Florian Weigend and Reinhart Ahlrichs. Ba- lanced basis sets of split valence, triple zeta va- lence and quadruple zeta valence quality for h to rn: Design and assessment of accuracy.Phy- sical Chemistry Chemical Physics, 7(18):3297– 3305, 2005

  33. [41]

    Thom H. Dunning. Gaussian basis sets for use in correlated molecular calculations. i. the atoms boron through neon and hydrogen.The Journal of Chemical Physics, 90(2):1007–1023, January 1989

  34. [42]

    Daniel Crawford and Henry F

    T. Daniel Crawford and Henry F. Schaefer. An introduction to coupled cluster theory for com- putational chemists. In Kenneth B. Lipkowitz and Donald B. Boyd, editors,Reviews in Com- putational Chemistry, chapter 2, pages 33–136. Wiley, 2000

  35. [43]

    Bartlett

    Rodney J. Bartlett. Coupled-cluster the- ory and its equation-of-motion extensions. WIREs Computational Molecular Science, 2(1):126–138, July 2011

  36. [44]

    Bartlett and Monika Musiał

    Rodney J. Bartlett and Monika Musiał. Coupled-cluster theory in quantum chemistry. Reviews of Modern Physics, 79(1):291–352, Fe- bruary 2007

  37. [45]

    Lyakh, Monika Musiał, Victor F

    Dmitry I. Lyakh, Monika Musiał, Victor F. Lo- trich, and Rodney J. Bartlett. Multireference nature of chemistry: The coupled-cluster view. Chemical Reviews, 112(1):182–243, December 2011

  38. [46]

    Tanenbaum.Organização Estrutu- rada de Computadores

    Andrew S. Tanenbaum.Organização Estrutu- rada de Computadores. Pearson, London, En- gland, 2015. Cited pages: 2–5, 28–30. 37

  39. [47]

    Patterson and John L

    David A. Patterson and John L. Hennessy.Or- ganização e Projeto de Computadores: A In- terface Hardware/Software. Elsevier, Rio de Janeiro, Brazil, 2017

  40. [48]

    Pearson, London, England, 2016

    William Stallings.Organização e Arquitetura de Computadores: Projetando para o Desem- penho. Pearson, London, England, 2016

  41. [49]

    Gordon E. Moore. Cramming more compo- nents onto integrated circuits.Electronics, 38(8):82–85, 1965

  42. [50]

    Quantum computers.nature, 464(7285):45–53, 2010

    Thaddeus D Ladd, Fedor Jelezko, Raymond Laflamme, Yasunobu Nakamura, Christopher Monroe, and Jeremy Lloyd O’Brien. Quantum computers.nature, 464(7285):45–53, 2010

  43. [51]

    Quantum computing in the nisq era and beyond.Quantum, 2:79, 2018

    John Preskill. Quantum computing in the nisq era and beyond.Quantum, 2:79, 2018

  44. [52]

    Quan- tum cryptography: Public key distribution and coin tossing

    Charles H Bennett and Gilles Brassard. Quan- tum cryptography: Public key distribution and coin tossing. InProceedings of IEEE Interna- tional Conference on Computers, Systems and Signal Processing, pages 175–179, 1984

  45. [53]

    Measurement of qubits.Physical Review A, 64(5):052312, 2001

    Daniel FV James, Paul G Kwiat, William J Munro, and Andrew G White. Measurement of qubits.Physical Review A, 64(5):052312, 2001

  46. [54]

    Can quantum-mechanical description of physical reality be considered complete? Physical review, 47(10):777, 1935

    Albert Einstein, Boris Podolsky, and Nathan Rosen. Can quantum-mechanical description of physical reality be considered complete? Physical review, 47(10):777, 1935

  47. [55]

    Ontheeinsteinpodolskyrosenpa- radox.Physics Physique Fizika, 1(3):195, 1964

    JohnSBell. Ontheeinsteinpodolskyrosenpa- radox.Physics Physique Fizika, 1(3):195, 1964

  48. [56]

    Rapid so- lution of problems by quantum computation

    David Deutsch and Richard Jozsa. Rapid so- lution of problems by quantum computation. Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences, 439(1907):553–558, 1992

  49. [57]

    Teleporting an unknown quantum state via dual classical and einstein- podolsky-rosen channels.Physical review let- ters, 70(13):1895, 1993

    Charles H Bennett, Gilles Brassard, Claude Crépeau, Richard Jozsa, Asher Peres, and Wil- liam K Wootters. Teleporting an unknown quantum state via dual classical and einstein- podolsky-rosen channels.Physical review let- ters, 70(13):1895, 1993

  50. [58]

    Quantum computatio- nal networks.Proceedings of the royal society of London

    David Elieser Deutsch. Quantum computatio- nal networks.Proceedings of the royal society of London. A. mathematical and physical sci- ences, 425(1868):73–90, 1989

  51. [59]

    Elementary gates for quantum computation.Physical review A, 52(5):3457, 1995

    Adriano Barenco, Charles H Bennett, Richard Cleve, David P DiVincenzo, Norman Margo- lus, Peter Shor, Tycho Sleator, John A Smo- lin, and Harald Weinfurter. Elementary gates for quantum computation.Physical review A, 52(5):3457, 1995

  52. [60]

    Quan- tum error correction below the surface code threshold.arXiv preprint arXiv:2408.13687, 2024

    Rajeev Acharya, Laleh Aghababaie-Beni, Igor Aleiner, Trond I Andersen, Markus Ansmann, FrankArute, KunalArya, AbrahamAsfaw, Ni- kita Astrakhantsev, Juan Atalaya, et al. Quan- tum error correction below the surface code threshold.arXiv preprint arXiv:2408.13687, 2024

  53. [61]

    Íons aprisionados como arquitetura para com- putação quântica.Revista Brasileira de Ensino de Física, 45:e20220218, 2022

    Gabriel PLM Fernandes, Alexandre C Ricardo, Fernando R Cardoso, and Celso J Villas-Boas. Íons aprisionados como arquitetura para com- putação quântica.Revista Brasileira de Ensino de Física, 45:e20220218, 2022

  54. [62]

    Scaling and networking a modular pho- tonic quantum computer.Nature, pages 1–8, 2025

    H Aghaee Rad, T Ainsworth, RN Alexander, B Altieri, MF Askarani, R Baby, L Banchi, BQ Baragiola, JE Bourassa, RS Chadwick, et al. Scaling and networking a modular pho- tonic quantum computer.Nature, pages 1–8, 2025

  55. [63]

    Nmr quantum computa- tion.Progress in Nuclear Magnetic Resonance Spectroscopy, 38(4):325–360, 2001

    Jonathan A Jones. Nmr quantum computa- tion.Progress in Nuclear Magnetic Resonance Spectroscopy, 38(4):325–360, 2001

  56. [64]

    Quantum coherence and en- tanglement with ultracold atoms in optical lat- tices.Nature, 453(7198):1016–1022, 2008

    Immanuel Bloch. Quantum coherence and en- tanglement with ultracold atoms in optical lat- tices.Nature, 453(7198):1016–1022, 2008

  57. [65]

    MIT press, Cambridge, MA, USA, 2022

    Thomas H Cormen, Charles E Leiserson, Ro- nald L Rivest, and Clifford Stein.Introduction to algorithms. MIT press, Cambridge, MA, USA, 2022

  58. [66]

    Variational quantum algorithms.Nature Reviews Physics, 3(9):625–644, 2021

    Marco Cerezo, Andrew Arrasmith, Ryan Bab- bush, Simon C Benjamin, Suguru Endo, Kei- suke Fujii, Jarrod R McClean, Kosuke Mitarai, Xiao Yuan, Lukasz Cincio, et al. Variational quantum algorithms.Nature Reviews Physics, 3(9):625–644, 2021

  59. [67]

    The history of noise [on the 100th anniversary of its birth].IEEE Signal Proces- sing Magazine, 22(6):20–45, 2005

    Leon Cohen. The history of noise [on the 100th anniversary of its birth].IEEE Signal Proces- sing Magazine, 22(6):20–45, 2005

  60. [68]

    A mathematical the- ory of communication.The Bell system tech- nical journal, 27(3):379–423, 1948

    Claude Elwood Shannon. A mathematical the- ory of communication.The Bell system tech- nical journal, 27(3):379–423, 1948

  61. [69]

    Error detecting and er- ror correcting codes.The Bell system technical journal, 29(2):147–160, 1950

    Richard W Hamming. Error detecting and er- ror correcting codes.The Bell system technical journal, 29(2):147–160, 1950. 38

  62. [70]

    Realizing repeated quantum error correc- tion in a distance-three surface code.Nature, 605(7911):669–674, 2022

    Sebastian Krinner, Nathan Lacroix, Ants Remm, Agustin Di Paolo, Elie Genois, Cathe- rine Leroux, Christoph Hellings, Stefania La- zar, Francois Swiadek, Johannes Herrmann, et al. Realizing repeated quantum error correc- tion in a distance-three surface code.Nature, 605(7911):6...

  63. [71]

    De- monstration of fault-tolerant universal quan- tum gate operations.Nature, 605(7911):675– 680, 2022

    Lukas Postler, Sascha Heuβen, Ivan Pogore- lov, Manuel Rispler, Thomas Feldker, Michael Meth, Christian D Marciniak, Roman Stricker, Martin Ringbauer, Rainer Blatt, et al. De- monstration of fault-tolerant universal quan- tum gate operations.Nature, 605(7911):675– 680, 2022

  64. [72]

    Quantum error cor- rection below the surface code threshold.Na- ture, 638(8052):920–926, 2024

    Google Quantum AI et al. Quantum error cor- rection below the surface code threshold.Na- ture, 638(8052):920–926, 2024

  65. [73]

    Trapped- ion quantum computing

    Albert Frisch, Alexander Erhard, Thomas Feldker, Florian Girtler, Max Hettrich, Wil- fried Huss, Georg Jacob, Christine Maier, Gre- gor Mayramhof, Daniel Nigg, et al. Trapped- ion quantum computing. InQuantum Soft- ware: Aspects of Theory and System Design, pages 251–283. Spri...

  66. [74]

    Über das paulische äquivalenzverbot.Zeitschrift für Physik, 47:631–651, 1928

    PascualJordanandEugenePaulWigner. Über das paulische äquivalenzverbot.Zeitschrift für Physik, 47:631–651, 1928

  67. [75]

    The bravyi-kitaev transformation for quantum computation of electronic struc- ture.The Journal of chemical physics, 137(22), 2012

    Jacob T Seeley, Martin J Richard, and Pe- ter J Love. The bravyi-kitaev transformation for quantum computation of electronic struc- ture.The Journal of chemical physics, 137(22), 2012

  68. [76]

    Barren plateaus in quantum neural network training landscapes.Nature commu- nications, 9(1):4812, 2018

    Jarrod R McClean, Sergio Boixo, Vadim N Smelyanskiy, Ryan Babbush, and Hartmut Neven. Barren plateaus in quantum neural network training landscapes.Nature commu- nications, 9(1):4812, 2018

  69. [77]

    Barren pla- teaus in variational quantum computing.Na- ture Reviews Physics, pages 1–16, 2025

    Martín Larocca, Supanut Thanasilp, Samson Wang, Kunal Sharma, Jacob Biamonte, Pa- trick J Coles, Lukasz Cincio, Jarrod R Mc- Clean, Zoë Holmes, and M Cerezo. Barren pla- teaus in variational quantum computing.Na- ture Reviews Physics, pages 1–16, 2025

  70. [78]

    New perspectives on unitary coupled-cluster theory

    Andrew G Taube and Rodney J Bartlett. New perspectives on unitary coupled-cluster theory. International journal of quantum chemistry, 106(15):3393–3401, 2006

  71. [79]

    Unconventional aspects of coupled-cluster theory

    Werner Kutzelnigg. Unconventional aspects of coupled-cluster theory. In Jirí Pittner Petr Cársky, Josef Paldus, editor,Recent Pro- gress in Coupled Cluster Methods: Theory and Applications, chapter12, pages299–356.Sprin- ger, Dordrecht, Netherlands, 2010

  72. [80]

    Cantheeigenstatesofamany- body hamiltonian be represented exactly using a general two-body cluster expansion?Physi- cal review letters, 84(10):2108–2111, 2000

    MarcelNooijen. Cantheeigenstatesofamany- body hamiltonian be represented exactly using a general two-body cluster expansion?Physi- cal review letters, 84(10):2108–2111, 2000

  73. [81]

    Some comments on the coupled cluster with generalized singles and doubles (ccgsd) an- satz.Chemical physics letters, 397(1-3):174– 179, 2004

    Debashis Mukherjee and Werner Kutzelnigg. Some comments on the coupled cluster with generalized singles and doubles (ccgsd) an- satz.Chemical physics letters, 397(1-3):174– 179, 2004

  74. [82]

    Generali- zed unitary coupled cluster wave functions for quantum computation.Journal of chemical theory and computation, 15(1):311–324, 2018

    Joonho Lee, William J Huggins, Martin Head- Gordon, and K Birgitta Whaley. Generali- zed unitary coupled cluster wave functions for quantum computation.Journal of chemical theory and computation, 15(1):311–324, 2018

  75. [83]

    Computational comple- xityinelectronicstructure.Physical Chemistry Chemical Physics, 15(2):397–411, 2013

    James Daniel Whitfield, Peter John Love, and Alán Aspuru-Guzik. Computational comple- xityinelectronicstructure.Physical Chemistry Chemical Physics, 15(2):397–411, 2013

  76. [84]

    A mathematical and computational review of hartree–fock scf methods in quantum chemis- try.Molecular Physics, 105(23-24):3057–3098, 2007

    Pablo Echenique and José Luis Alonso. A mathematical and computational review of hartree–fock scf methods in quantum chemis- try.Molecular Physics, 105(23-24):3057–3098, 2007

  77. [85]

    A quantum computing view on unitary coupled cluster theory.Che- mical Society Reviews, 51(5):1659–1684, 2022

    Abhinav Anand, Philipp Schleich, Sumner Alperin-Lea, Phillip WK Jensen, Sukin Sim, Manuel Díaz-Tinoco, Jakob S Kottmann, Matthias Degroote, Artur F Izmaylov, and Alán Aspuru-Guzik. A quantum computing view on unitary coupled cluster theory.Che- mical Society Reviews, 51(5):165...

  78. [86]

    On the product of semi-groups of operators.Proceedings of the American Mathematical Society, 10(4):545–551, 1959

    Hale F Trotter. On the product of semi-groups of operators.Proceedings of the American Mathematical Society, 10(4):545–551, 1959

  79. [87]

    Masuo Suzuki. Generalized trotter’s formula and systematic approximants of exponential operators and inner derivations with applicati- ons to many-body problems.Communications in Mathematical Physics, 51(2):183–190, 1976

  80. [88]

    Gene- ralized swap networks for near-term quantum computing.arXiv preprint arXiv:1905.05118, 2019

    Bryan O’Gorman, William J Huggins, Elea- nor G Rieffel, and K Birgitta Whaley. Gene- ralized swap networks for near-term quantum computing.arXiv preprint arXiv:1905.05118, 2019. 39

  81. [89]

    Quantum circuits for strongly corre- lated quantum systems.Physical Review A, 79(3):032316, 2009

    Frank Verstraete, J Ignacio Cirac, and José I Latorre. Quantum circuits for strongly corre- lated quantum systems.Physical Review A, 79(3):032316, 2009

  82. [90]

    Quan- tum simulation of electronic structure with li- near depth and connectivity.Physical review letters, 120(11):110501, 2018

    Ian D Kivlichan, Jarrod McClean, Nathan Wi- ebe, Craig Gidney, Alán Aspuru-Guzik, Gar- net Kin-Lic Chan, and Ryan Babbush. Quan- tum simulation of electronic structure with li- near depth and connectivity.Physical review letters, 120(11):110501, 2018

  83. [91]

    Nobel lecture: Quantum che- mical models.Reviews of Modern Physics, 71(5):1267, 1999

    John A Pople. Nobel lecture: Quantum che- mical models.Reviews of Modern Physics, 71(5):1267, 1999

  84. [92]

    Precise mea- surement of quantum observables with neural- network estimators.Phys

    Giacomo Torlai, Guglielmo Mazzola, Giuseppe Carleo, and Antonio Mezzacapo. Precise mea- surement of quantum observables with neural- network estimators.Phys. Rev. Res., 2:022060, Jun 2020

  85. [93]

    Pranav Gokhale, Olivia Angiuli, Yongshan Ding, Kaiwen Gui, Teague Tomesh, Martin Su- chara, Margaret Martonosi, and Frederic T. Chong. Minimizing state preparations in va- riational quantum eigensolver by partitioning into commuting families.arXiv preprint ar- Xiv:1907.13623, 2019

  86. [94]

    Izmaylov

    Vladyslav Verteletskyi, Tzu-Ching Yen, and Artur F. Izmaylov. Measurement optimization in the variational quantum eigensolver using a minimum clique cover.The Journal of Chemi- cal Physics, 152(12):124114, 03 2020

  87. [95]

    Measurements of quantum ha- miltonians with locally-biased classical sha- dows.Communications in Mathematical Phy- sics, 391:951–967, 2022

    Charles Hadfield, Sergey Bravyi, Roger Ray- mond, et al. Measurements of quantum ha- miltonians with locally-biased classical sha- dows.Communications in Mathematical Phy- sics, 391:951–967, 2022

  88. [96]

    Does provable absence of barren plateaus imply clas- sical simulability? or, why we need to rethink variational quantum computing.arXiv pre- print arXiv:2312.09121, 2023

    Marco Cerezo, Martin Larocca, Diego García- Martín, Nelson L Diaz, Paolo Braccia, Enrico Fontana, Manuel S Rudolph, Pablo Bermejo, Aroosa Ijaz, Supanut Thanasilp, et al. Does provable absence of barren plateaus imply clas- sical simulability? or, why we need to rethink variati...

  89. [97]

    Reducingthe resources required by adapt-vqe using coupled exchange operators and improved subroutines

    Mafalda Ramôa, Panagiotis G Anastasiou, Luis Paulo Santos, Nicholas J Mayhall, Edwin Barnes, andSophiaEEconomou. Reducingthe resources required by adapt-vqe using coupled exchange operators and improved subroutines. npj Quantum Information, 11(1):1–19, 2025. 40

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